A variety of gene therapy approaches have been developed to achieve antitumor effects. In this regard, the approach of molecular chemotherapy is designed to achieve selective eradication of carcinoma cells via an expressed toxin gene. It has also been observed that tumor cells transduced with selected toxin genes can exert a noxious effect, a so-called bystander effect, on surrounding, nontransduced tumor cells. This phenomenon, therefore, makes possible the transduction of only a minority of tumor cells with the subsequent potential to effect a much larger tumor cell kill. In addition, it has been suggested that molecular chemotherapy induced tumor cell toxicity may elicit a potent antitumor immune response. It is, therefore, their hypothesis that molecular chemotherapy strategies can be safely and effectively implemented in the context of ovarian cancer. Specifically, this proposal intends to determine: (1) the maximally tolerated single dose (MTD) and the spectrum of toxicities encountered with; (2) the safety of administration of; (3) the molecular efficacy of, and (4) the immune modulating effects of intraperitoneally delivered recombinant adenovirus encoding the herpes simplex virus thymidine kinase (HSV-TK) gene given in combination with intravenous ganciclovir (GCV) in previously treated ovarian and extraovarian cancer patients. To achieve these specific aims, this research proposal includes a human gene therapy protocol for ovarian and extraovarian cancer patients with persistent or recurrent disease. This phase I protocol will identify the MTD of the proposed HSV-TK/GC methodology and its associated clinical toxicity. Secondly, safety studies will be performed in the context of this trial to determine if the viral vector employed elicits a host immune response, is expressed in transduced tumor cells, and propagates or replicates in the target cells. Molecular efficacy will be performed to determine if, in the context of human diseases, the HSV-TK gene transfects targeted ovarian cancer cells. Lastly, studies will be performed to see if the proposed therapy enhances the CTL response to tumor. The proposed gene therapy strategy has been highly promising in in vitro and in vivo studies. It is anticipated that the experiments described herein would establish the safety and efficacy of this approach in human subjects with ovarian cancer and allow the rapid evaluation of the clinical utility of this novel agent in future phase II/III studies.